The murder mystery drama, which stars John Nettles, averaged 4.53m (20.2%) on ITV1 between 8pm and 10pm.
The programme helped ITV beat the BBC in primetime, after Celebrity Masterchef brought in 4.11m (19%) in the 8pm hour and Traffic Cops took 3.86m (16.7%) in the 9pm hour.
Earlier on BBC One, new series Penguin Island appealed to 3.29m (17.6 %) between 7.30pm and 8pm, outperforming ITV1's Lion Country, which grabbed 3.02m (16.2%) in the same timeslot.
However, Emmerdale performed well for ITV1 in the peaktime soap ratings, with 6.4m (33.8%) tuning in between 7pm and 7.30pm. A further 122k (0.6%) watched the programme on ITV1 HD.
A new episode of Katie & Alex: For Better For Worse appealed to 976k (4.2%) in the 9pm hour, which was the largest multichannel audience of the night. The programme also pulled in 221k (1.2%) on timeshift.
The latest Big Brother took 2.4m (13.6%) for Channel 4 between 10pm and 11.10pm. A further 315k (1.4%) watched the show on Channel 4 +1.
How To Look Good Naked attracted 1.74m (8.1%) from 8pm and 235k (1.3%) on timeshift. It was followed by documentary The Men Who Jump Off Buildings, which took 1.73m (7.5%) in the 10pm hour and 149k (1.6%) on Channel 4 +1.
Live coverage of the European Athletics Championships pulled in 2.1m (12.1%) on BBC Two between 5pm and 9pm.
After the athletics, Coast brought in 2.6m (11.2%) on BBC Two in the 9pm hour, before comedy panel show QI secured 1.88m (9.2%) between 10pm and 10.30pm.
Escape From Dunkirk attracted 563k (3%) to Five between 7.30pm and 8pm, before Emergency Bikers took 999k (4.6%) in the 8pm hour.
NCIS secured 1.09m (4.7%) for Five between 9pm and 10pm, and it was followed by Law & Order: Criminal Intent, which took 1.11m (5.9%) in the 10pm hour.
Overall, ITV1 won primetime with 19.2% against BBC One's 17.9%. BBC Two came in third with 11.3%, followed by Channel 4 with 8.1% (+1: 1%) and Five with 4.3%.
BARB ratings data supplied by Attentional